1. Field of the Invention
The field of the invention relates to an electronic cigarette personal vapouriser, also known as an electronic cigarette (e-cig or e-cigarette), vapestick, modding kit, personal vaporizer (PV), advanced personal vaporizer (APVs) or electronic nicotine delivery system (ENDS). In this specification, we will typically use ‘PV’ or ‘e-cigarette’ as the generic term. A PV vapourises ‘e-liquid’ or vaping substance to produce a non-pressurised vapour or mist for inhalation for pleasure or stress-relief, replicating or replacing the experience of smoking a cigarette. An ‘E-liquid’ or vaping substance is a liquid (or gel or other state) from which vapour or mist for inhalation can be generated and whose primary purpose is to deliver nicotine.
PVs are therefore mass-market consumer products that are equivalent to cigarettes, and are typically used by smokers as part of a cigarette reduction or cessation program. The main ingredients of e-liquids are usually a mix of propylene glycol and glycerine and a variable concentration of tobacco-derived nicotine. E-liquids can include various flavourings and also come with varying strengths of nicotine; users on a nicotine reduction or cessation program can hence choose decreasing concentrations of nicotine, including at the limit zero concentration nicotine e-liquid. The term ‘e-liquid’ will be used in this specification as the generic term for any kind of vaping substance. E-cigarette PVs were first conceived in 1963 and for the last 50 years of development have generally been seen as a separate and distinct category compared with conventional medicinal delivery systems. To emphasise the difference over medicinal devices, we will also in this specification use the term ‘e-cigarette PV’, as opposed to the term ‘PV’.
Despite this sector being over 50 years old, there are still many practical problems that have not yet been solved and that are a barrier to e-cigarette PVs achieving mass-market success; they are still a long way from replacing conventional cigarettes. If they were to largely replace cigarettes, then some experts state that large-scale adoption could bring significant public health benefits. Writing in the British Journal of General Practice, DOI: 10.3399/bjgp14X681253, published 1 Sep. 2014, Prof Robert West and Dr Jamie Brown from University College London stated that “For every million smokers who switched to an e-cigarette we could expect a reduction of more than 6000 premature deaths in the UK each year, even in the event that e-cigarette use carries a significant risk of fatal diseases, and users were to continue to use them indefinitely.”
2. Technical Background
PVs are typically battery-powered devices which simulate tobacco smoking by producing inhalable vapour (typically propylene glycol and nicotine). They generally use a heating element known as an atomizer, that vaporizes a liquid solution known as e-liquid or ‘juice’. E-liquids usually contain a mixture of propylene glycol, vegetable glycerin, nicotine, and flavorings, while others release a flavored vapor without nicotine. Vaporization is an alternative to burning (smoking) that avoids the inhalation of many irritating toxic and carcinogenic by-products. Apart from simulating tobacco smoking, the electronic vapouriser can also be used as a smoking-cessation aid or for nicotine (or other substance) dosage control.
Most electronic cigarettes take an overall cylindrical shape although a wide array of shapes can be found: box, pipe styles etc. First generation electronic cigarettes were usually designed to simulate cigarettes in their use and appearance. They are often called ‘cig-a-likes’. Cig-a-likes are usually disposable, low cost items and the user-experience is often quite poor. New generation electronic cigarettes, often called mods, modding-kits or APV's (advanced personal vaporizer) have an increased nicotine-dispersal performance, housing higher capacity batteries and come in various form factors, including metal tubes and boxes. Many electronic cigarettes are composed of standardized replaceable parts that are interchangeable from one brand to the other, while disposable devices combine all components into a single part that is discarded when its liquid is depleted. Common components include a liquid delivery and container system like a cartridge or a tank, an atomizer, and a power source.
Atomizer
An atomizer generally consist of a small heating element responsible for vaporizing e-liquid, as well as a wicking material that draws liquid in. Along with a battery, the atomizer is the central component of every personal vaporizer. Differences between atomizers cause differences in the ingredients and their concentrations delivered to users, even when the same liquid is used.
A small length of resistance wire is coiled around the wicking material and then connected to the positive and negative poles of the device. When activated the resistance wire (or coil) quickly heats up, thus turning the liquid into a vapor, which is then inhaled by the user.
Wicking materials vary greatly from one atomizer to another but silica fibers are the most commonly used in manufactured atomizers. A wide array of atomizers and e-liquid container combinations are available.
Cartomizers
A cartomizer (a portmanteau of cartridge and atomizer) or ‘carto’ consists of an atomizer surrounded by a liquid-soaked poly-foam that acts as an e-liquid holder. It is usually disposed of once the e-liquid acquires a burnt taste, which is usually due to an activation when the coil is dry or when the cartomizer gets consistently flooded (gurgling) because of sedimentation of the wick. Most cartomizers are refillable even if not advertised as such.
Cartomizers can be used on their own or in conjunction with a tank that allows more e-liquid capacity. In this case the portmanteau word of “carto-tank” has been coined. When used in a tank, the cartomizer is inserted in a plastic, glass or metal tube and holes or slots have to be punched on the sides of the cartomizer to allow liquid to reach the coil.
Clearomizers
Clearomizers or “clearos”, not unlike cartotanks, use a clear tank in which an atomizer is inserted. Unlike cartotanks, however, no poly-foam material can be found in them.
There are a lot of different wicking systems employed inside of clearomizers to ensure good moistening of the wick without flooding the coil. Some rely on gravity to bring the e-liquid to the wick and coil assembly (bottom coil clearomizers for example) whereas others rely on capillary action and to some degree the user agitating the e-liquid while handling the clearomizer (top coil clearomizers)
Power
Most portable devices contain a rechargeable battery, which tends to be the largest component of an electronic cigarette. The battery may contain an electronic airflow sensor whereby activation is triggered simply by drawing breath through the device, while other models employ a power button that must be held during operation. An LED to indicate activation may also be employed. Some manufacturers also offer a cigarette pack-shaped portable charging and re-filling case (PCC), which contains a larger battery capable of charging e-cigarettes. Devices aimed at more experienced users may sport additional features, such as variable power output and support of a wide range of internal batteries and atomizer configurations and tend to stray away from the cigarette form factor. Some cheaper recent devices use an electret microphone with a custom IC to detect airflow and indicate battery status on the included blue LED.
Variable Power and Voltage Devices
Variable voltage or power personal vaporizers are devices that contain a built in electronic chip that allows the user to adjust the power that goes through the heating element. They usually incorporate a LED screen to display various information. Variable PV's eliminate the need of having to replace an atomizer with another one of lower or higher electrical resistance to change the intensity of the vapour (the lower the resistance, the higher the vapour intensity). They also feature voltage regulation and some battery protection.
Some of these devices offer additional features through their menu system such as: atomizer resistance checker, remaining battery voltage, puff counter, activation cut-off etc.
E-Liquid
E-liquid, e-juice or simply “juice”, refers to a liquid solution that produces a mist or vapour when heated by an atomizer. The main ingredients of e-liquids are usually a mix of propylene glycol (PG), vegetable glycerin (VG), and/or polyethylene glycol 400 (PEG400), sometimes with differing levels of alcohol mixed with concentrated or extracted flavorings; and a variable concentration of tobacco-derived nicotine. There is variability in the purity, kinds and concentrations of chemicals used in liquids, and significant variability between labeled content and concentration and actual content and concentration
E-liquid is often sold in bottles or pre-filled disposable cartridges, or as a kit for consumers to make their own. Components are also available individually and consumers may choose to modify or boost their flavor, nicotine strength, or concentration with various offerings. Pre-made e-liquids are manufactured with various tobacco, fruit, and other flavors, as well as variable nicotine concentrations (including nicotine-free versions). The standard notation “mg/ml” is often used in labeling for denoting nicotine concentration, and is sometimes shortened to a simple “mg”.
Source acknowledgement for this Technical Background section: Wikipedia entry on e-cigarettes.
3. Discussion of Related Art
The patent literature in this field is quite extensive, with the earliest e-cigarette PV dating from 1963.
Some of the more relevant patent disclosures in this space include the following. We highlight some of the main reasons why each item of prior art lacks relevance.
US 2014/020697 Liu.                Just a PV charging device        No e-liquid re-filling capability        No user-replaceable e-liquid cartridge        No data processor with communications capability        
CN 202679020 Chen:                Just a PV charging device        No e-liquid re-filling capability        No user-replaceable e-liquid cartridge        No data processor with communications capability        
US 2013/342157 Liu                Just a PV charging device        No e-liquid re-filling capability        No user-replaceable e-liquid cartridge        No data processor with communications capability        
CN 201630238 Jian                Just a PV charging device        No e-liquid re-filling capability        No user-replaceable e-liquid cartridge        No data processor with communications capability        
WO 2011/095781 Kind                Not e-liquid, e-cigarette related        No e-liquid re-filling capability—fills a pressurised gas instead        No user-replaceable e-liquid cartridge (the gas canister is not described as being user-replaceable and doing so would in fact require the user to take the entire unit to pieces, so it teaches away from user-replaceability)        No electrical charging capability (device has no battery)        No data processor with communications capability        
US 2012/167906 Gysland                Not a PV charging device        Just an e-liquid filling device, using a standard e-liquid squeezable bottle; the user unscrews the PV, separating it into an atomiser portion and an e-liquid chamber portion, and then screws the e-liquid chamber portion into one end of this device and screws the squeezable bottle into the other end of this device and then squeezes the bottle to transfer the e-liquid over.        No charging capability        No data processor with communications capability        
WO 2011/026846 Wedegree                Not e-liquid PV related—instead, it's a propane powered heat-based device        No e-liquid re-filling, just re-fills a device with liquid propane        Mouthpiece is removed before the device is inserted for gas re-filling        No charging capability        No user-replaceable cartridge        No data processor with communications capability        
WO 2009/001078 Kind                Not e-liquid, e-cigarette related        No e-liquid fills pressurised gas instead        No user-replaceable cartridge (gas canister in the refill unit is itself re-filled)        No charging capability        No data processor with communications capability        
For completeness, we mention also another item of non-analogous art, which is firmly in the medical inhalation field and lacks any specific reference to e-cigarettes or nicotine delivery. The field of this invention is rather different from medical inhalation devices, such as asthma inhalers or other metered dose inhalers, since cigarette smoking is very clearly not a medicinal activity. Specifically, the mind-set of the e-cigarette designer is to replicate as closely as possible the non-medicinal cigarette smoking experience, but without combusting tobacco. Metered dose inhalers on the other hand are typically designed for accurate, rapid, and very occasional (e.g. emergency-only) oral delivery of one or two doses of pressurised medicinal aerosol; the user experience of a PV is quite different, with relatively slow, but frequently repeated inhalations of a mist or vapour from a non-pressurised source; the experience is designed to be similar to, and hence an effective replacement for, the experience of smoking a conventional tobacco cigarette. One example of a metered dose inhaler is shown in U.S. Pat. No. 6,637,430 Ponwell. This lacks relevance for the following reasons:                No explicit relevance to e-cigarettes—primarily, this is a piezo-electric metered dose inhaler system for respiratory medicines—a very different field from e-cigarette PVs        Not suitable for re-filling PVs since it uses a needle in the case to puncture a rubber septum in the metered dose inhaler (a conventional approach used in the medicinal context where maintaining sterility of the medicament is key). But this rubber septum would degrade and tear with more than a few re-insertions; this is not an issue for a metered dose inhaler which is used relatively infrequently and sterility of the medicament is more important than durability of the medicament transfer mechanism.        No user-replaceable liquid cartridge (in fact, teaches re-filling the medicament container, so it is not a user-replaceable cartridge)        Is not a combined carrying and storage case for the metered dose inhaler        
Emphasising the distance between the field of metered dose inhalers and e-cigarette PV design, one of the many problems facing the designer of an e-cigarette PV is how to minimse any toxins in the vapour produced by the PV.
For example, in the paper in the New England Journal of Medicine, ‘Hidden Formaldehyde in E-Cigarette Aerosols’ N Engl J Med 2015; 372:392-394, the authors describe how they tested for the presence of formaldehyde-releasing agents (whose safety when inhaled is not fully understood) in the vapour of an e-cigarette PV with a variable voltage power source: ‘At low voltage (3.3 V), we did not detect the formation of any formaldehyde-releasing agents (estimated limit of detection, approximately 0.1 μg per 10 puffs). At high voltage (5.0 V), a mean (±SE) of 380±90 μg per sample (10 puffs) of formaldehyde was detected as formaldehyde-releasing agents.’ They go on to state ‘How formaldehyde-releasing agents behave in the respiratory tract is unknown, but formaldehyde is an International Agency for Research on Cancer group 1 carcinogen.’ One solution would appear to be to ensure that e-cigarette PVs run at low voltage (e.g. 3.3V) and not higher voltages, like 5V. But the problem that then arises is that the PV current has to be higher for a good ‘vaping’ experience, and that in turn means that (a) the PV battery runs down more quickly, and (b) the e-liquid is consumed more rapidly.
This is inconvenient with conventional designs of PV because recharging or replacing a battery takes time and because re-filling with e-liquid takes time; users would for example then need to carry around spare batteries or charging cables and e-liquid bottles. This is very different from the relatively straightforward and simple experience (and, to smokers, deeply attractive ritual) of opening a pack of conventional cigarettes and just lighting up. Because we see replicating the behavioural aspects of the cigarette smoking user experience as key to a successful product, these are major drawbacks for conventional PV designs.
One solution is to use a large ‘modding-kit’ type PV with a very large capacity battery that can run at the low 3.3V voltage associated with no formaldehyde release and a large e-liquid reservoir. These devices can be the size of several packets of cigarettes, and so the user sacrifices easy portability. But the performance or user experience can be good, since these devices can produce good quantities of vapour, without the need for frequent and inconvenient battery re-charging or replacement and e-liquid re-filling. When e-liquid does need to be replenished however, that is typically done by dis-assembling the unit to expose the reservoir and to then squeeze e-liquid into the reservoir from a small bottle; this can be slow and cumbersome; users often then carry around a replacement bottle or e-liquid, especially if they are using e-cigarettes to quit tobacco smoking, since if they were to run out of e-liquid, then the temptation to buy a packet of cigarettes to smoke could prove hard to resist. And this complex e-liquid re-filling process clearly has none of the simplicity or attractive ritual of opening a packet of cigarettes and lighting up.
An ideal solution would be an e-cigarette PV with the form factor of a conventional cigarette, and with the best aspects of the performance and user experience of a large modding kit type PV. This specification describes such a solution. The solution is designed to replicate many of the key behavioural and experiential aspects that make smoking attractive to smokers (e.g. the tactile satisfaction of holding a cigarette packet and opening the lid and withdrawing a cigarette; the action of holding a slim cigarette; the simplicity of the user's only action being to light up). Replicating these user experience aspects is we believe key to the successful mass-market adoption of e-cigarettes and hence delivering on their considerable public health potential.